Switch relay for use in dynamoelectric machines



June 14, 1966 c. E. LINKOUS 3,256,403

SWITCH RELAY FOR USE IN DYNAMOELECTRIC MACHINES 4 Sheets-Sheet 1 Filed Jan. 2, 1964 I IIIII ll)! INVENTOR.

Claw/Is E L/fl/Kous, 17 7M M Attorney- June 14, 1966 c. E. LINKOUS 3,256,403

SWITCH RELAY FOR USE IN DYNAMOELEGTRIC MACHINES Filed Jan. 2, 1964 4 Sheets-Sheet 2 o INVENTOR. 62a w's 5. Z. 01/250415 145$ orvreg.

June 14, 1966 c. E. LINKOUS 3,256,403

SWITCH RELAY FOR USE IN DYNAMOELECTRIC MACHINES Filed Jan. 2,1964 4 Sheets-Sheet 4 INVENTOR. 6Z0 ws .6 Z 01%us,

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United States Patent 3,256,403 SWITCH RELAY FOR USE IN DYNAMOELECTRIC MACHINES Clovis E. Linkous, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Filed Jan. 2, 1964, Ser. No. 335,319 14 Claims. (Cl. 200--91) This invention relates in general to electromagnet switch relays and more particularly to an electro-magnetically operated switch relay especially suitable for controlling the auxiliary or start winding circuit of split phase induction type electric motors.

In certain types of dynamoelectric machines, such as single phase, split phase induction electric motors having both main and start windings, electromagnetically operated switch relays are employed for controlling the energization of the start winding circuit. These relays customarily include a core structure carrying a coil in circuit with one of the machine windings and a cooperating movable armature responsive to the energization of the coil. The core and armature together define a variable magnetic air gap with the ar-mature serving to actuate the movable ,contact of the relay. Unfortunately, the relays are usually rather complicated and costly in design to achieve a longevity over 100,000 cycles of operation, far less than the number of cycles required to approach the life expectancy of the motor in which they are used. In an attempt to provide a non-position sensitive type relay, that is a relay which may be mounted at any angle without adversely affecting its operation, prior relays required a large number of parts, rugged in structure, which are difiicult and expensive to assemble together, particularly for relays interrupting loads over one kilovolt-ampere (kva.).

Another problem with this type of relay is the noise it produces during operation which is particularly noticeable and objectionable when the relay is employed in motors used for domestic applications, such as in typewriters, appliances, and the like.

It is therefore a general object of the present invention to provide an improved switch relay, and it is a more specific object to provide a relay especially adopted for use in the control of an electric motor auxiliary winding, which overcomes the deficiencies mentioned above.

It is still another object of the invention to provide a relatively inexpensive relay which incorporates easily assembled components, is quiet in operation, and provides a positive over-center motion of the movable switch contact as it moves away from the stationary contact.

It is another object of the invention to provide a switch relay which is compact, yet rugged in construction, is not sensitive to the position in which it is mounted, and is capable of well over 1,000,000 cycles of trouble-free operation.

It is a further object of the present invention to provide an improved switch relay which may be conveniently mounted within a dynamoelectric machine adjacent frame and stator.

In carrying out the objects of the present invention in one form I provide an improved switch relay having first.

and second switch contacts in which the first contact is carried on the free end of a cantilever type spring blade. The blade supports a magnetizable armature for swinging movement relative to an electromagnet core and applies a bias to the armature for maintaining one end on the core and the free end normally away from the core. The blade also includes over-center toggle spring mechanism intermediate its ends for producing a snap action of the first contact toward and away from the second one. The net force of the blade is greater than that of the toggle. A pair of generally U-shaped brackets mount the spring blade and armature in spaced relation to permit relative movement between the armature and the toggle. This is accomplished by sandwiching the blade, in the vicinity of the over-center toggle, between the respective legs of the brackets which are connected together. The armature is in turn secured to the bight section of the lower bracket. When the armature is in the open position, a section thereof is biased away from the core by the spring blade, and the contacts are maintained in the closed position by the net forces of the springs. In addition, the portion of the spring blade between the brackets and its own support places a torque on the supported end of the armature to hold it on the core. Upon actuation of the armature caused by the core, overcoming the spring bias on the armature, its biased section is swung toward the core causing operation of the over-center toggle to snap the contacts apart. By a further aspect the relay includes a rocklable element for producing impact on the free end of the spring blade to impart momentum to the blade away from the second contact. In addition, the core of the relay is formed to provide quiet operation for the armature.

The subject matter which I regard as my invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. My invention, itself, however, both as to its organization and method of operation, together with further objects and advantages thereof may best be understood by reference to the following description taken in connection with the accompany-ing drawings. 1

In the drawings:

FIG. ,1 is a fragmentary plan elevational view, partly broken away, showing one end of a dynamoelectric machine having one form of the switch relay of the present invention;

FIG. 2 is a fragmentary side elevational view, partly broken away and in section of the same dynamoelectric machine end illustrated in FIG. 1 to show further details of the switch relay seen in FIG; 1;

FIG. 3 is an enlarged partially exploded view in perspective of the relay and support seen in FIG. 1;

FIG. 4 is a view of the relay armature assembly taken along line 4-4 in FIG. 3;

FIG. 5 is an ex-polded view of the relay armature assembly shown in FIG. 3;

FIG. 6 is a fragmentary enlarged view in perspective of the impact mechanism of the relay of FIG. 3;

FIG. 7 is a schematic representation of the winding control circuit for the dynamoelectric machine of FIG. 1;

FIG. 8 is an enlargedside elevational view of a switch relay incorporating another form of my invention;

FIG. 9 is a view taken along line 9-9 in FIG. 8; and

FIG. 10 is an exploded view in perspective of the core and coil structure of the relay seen in FIG. 8.

Turning now to the drawings in more detail and in particular to FIGS. 1-7 inclusive, the switch relay of the first embodiment has been shownin connection with a single phase induction electric motor 20 of the resistance split phase type. The motor includes a laminated stator core 21 of standard construction, formed by a stacked plurality of laminations punched from relatively thin magnetic material, the illustrated core having a generally circular peripheral contour. A distributed main or running winding 22 is arranged in stator winding accommodating slots in the usual way with winding end turns 23 projecting beyond each side face 24 of the core. For reasons of simplicity of illustration and brevity of description, only one side of motor 20 has been shown in FIGS. 1 and 2. An auxiliary or start winding 26 is displaced electrical degrees from the main winding in the slots for the usual reasons. Each winding is wound with a number of turns of insulated wire; e.g., magnet wire, to form winding poles in the well known manner, the windings being insulated from the core by standard slot lines 27. Both windings are adapted to be energized during starting conditions, while only the main winding is excited for running operation as will be explained more fully hereinafter.

The stator core is mounted within a cylindrical central shell 31, fabricated of sheet material like steel, of a motor frame, as by welding the stator to the shell at angularly spaced apart locations. Shell 31 extends axially beyond winding end turns 25, terminated on each side in an edge 32 which is suitably connected to a cast end shield 33 of an end frame. The connection shown in FIGS. 1 and 2 is of the rabbet type, with a number of angularly spaced apart through'bolts 34 securing the parts vfirmly together. Each end shield incorporates a central hub 35 mounting bearing for rotatably supporting one end of a shaft 3, which in turn, carries a conventional rotor (not shown) having a cast squirrel cage type winding formed with end rings partially seen and indicated in FIGS. 1 and 2 by numeral 37.

For controlling the circuit of the start winding 26, the motor of the exemplification incorporates an improved switch relay 40 constructed in accordance with one embodiment of the present invention shown in FIGS. 1-7 inclusive. The relay is formed with an E-shaped core structure, fabricated of solid magnetic material such as iron or steel, having three spaced apart magnetizable leg sections 42, 43 and 44 integrally joined together at one end by an elongated magnetic yoke section 45. Mounted on the middle leg 43 is an excitation relay winding or coil 47 which is wound of suitable enameled wire; e.g., magnet wire adapted to be energized when the motor speed reaches a predetermined value. Toward this end, the terminations 48 of the coil 47 are suitably attached by crimped connectors 49 to the terminations of a sensing coil 51 (FIG. 7) arranged in the start axis of the start winding. The precise manner in which this construction operates will be brought out more fully a little later in the description. Coil 47 may be insulated from the relay core in any satisfactory manner, as by fiber board 52, mylar, or other well recognized electrical insulation. A shading coil 53, formed of copper or some other nonferrous conductiving material, encircles outermost leg 43 for providing a delay in the change of fiux through the encircled or shaped leg section in the well understood way.

An elongated armature element mechanism 55, built of magnetiz able material like steel, is supported above the free ends of the respective leg sections for cooperation therewith to control the actuation of movable and stationary switch contacts 56, 57 respectively, which in the illustrated exemplification, are serially connected in the start winding circuit of the motor. Preferably, when armature 55 is in its actuated or closed position, that is, a zero air gap with the core, it should rest on legs 42 and shaded leg 44. Thus middle leg 43 carrying excitation coil 41 should be slightly below the other two legs. With the flux density of leg 44 being somewhat less than leg 43, a lower magnetic force results which in turn produces less friction between armature end 55a and the core to provide good seating between the parts. In addition, legs 42 and 44 produce a quite operation for the armature as it moves between the open or non-actuated position (FIG. 7) and the actuated position (FIG. 1).

Turning once again to the switch contacts, it will be :seen in FIGS. 3 and 5, movable contact 56 is carried by .an elongated cantilever type spring blade 61 formed of electrically conducting material and having an extension 62 of J configuration suitably attached to a support. It should be noted at this time that the illustrated means for supporting the component parts of switch relay 40, is of the type disclosed more fully and claimed in my co-pending patent application Serial Number 335,243 filed January 2, 19,64, As disclosed in that application,

the support, generally identified herein by numeral .70, is a single molded piece, fabricated from thermoresponsive material such as cured epoxy resin. As pic'- tured in FIG. 3, the support, among other things, includes a start winding switch mounting section 71 having a generally rectangular chamber or cavity defined by bottom wall 73, curved outer Wall 74, inner wall 75, and side walls 76, 77. The relay of the present invention has its core secured to bottom wall 73, with the yoke positioned next to wall 75,. by a rivet 46 which projects laterally through yoke section and into wall 73. A recess 78 is formed in section 71, outwardly of walls 76 and 77, for accommodating relay coil connections 49. Channels 79 communicate between the chamber and each recess through side walls 76 and 77 respectively to allow passage of the relay coil wire extremities to the connectors. This construction electrically isolates and protects connectors 49.

In order to support properly the switch contact blades of the relay under consideration, outer wall is stepped at either end of the chamber, as indicated at 83, and terminatesin integral enlargements 84 and 85. It is to enlargement 84 that movable blade extension 62 is secured such that blade 61 projects from the pivot at 62a and into the chamber with the free end of the blade having contact 56 disposed away from wall 74. This allows the blade to move freely between wall 74 and the core. A pair of identical rivets 87 firmly attaches blade 61 to its supporting enlargement. In its assembled position blade 61 extends entirely over and beyond the free ends. Stationary L-shaped blade 58, carrying contact 57 on the side facing wall 74 but below blade 61 for cooperation with contact 56, has a male terminal end 59 and is similarly attached to the other enlargement by a pair of rivets 89.

By one of the features of the present invention, blade 61 pivotally supports armature 55 such that its ends 55a is in effect, but not physically, hinged to the end of outermost leg 42. It thus supports armature end or section 55b for swinging movement between the actuated and nonactuated or open positions previously mentioned while applying a continuous bias on the armature to retain it in the open position. The spring blade also includes an over-center toggle mechanism to produce snap action .of the free end of the blade and contact into and out of engagement with contact 57 as the blade is moved in response to movement of the armature. More specifically, spring blade 61 has a depending bend 61a over anmature end 55a to seat the armature on leg 42. The blade also includes a positive spring constant which is greater than that for the toggle mechanism. With the armature maintained in the unoperated position, contacts 56, 57 will be closed. When armature is actuated, the over-center mechanism causes contact 56 to snap away from its closed position to the open position seen in FIG. 1. Upon release of the armature by the core blade 61 which has a greater spring force at all times as compared with the toggle mechanism moves armature 55 to its non-actuated position (FIG. 7) and the toggle mechanism moving over center, snaps contact 56 to the closed position.

FIGS. 3, 4, and 5 reveal the illustrated over-center toggle mechanism carried by blade 61. In this regard, the blade has two generally parallel longitudinal slots 63 and 64 cut into it near contact 56 which are joined to furnish spaced apart tension arms 65 and 66. An overcenter coil spring 67 is positioned in the space between the arms and has one end hooked into each arm to hold the arms under tension. This in turn produces a curve in the regions of blade 61 on either side of slots 63 and 64 which acts to move contact 56 into or out of engagement with stationary contact 57.

Referring now to the manner in which blade 61' supportsa-rmature 55, and still to FIGS. 3, 4, and 5 the support is provided by a pair of opposed brackets 91, which clamp a part of the spring blade 61 therebetween and hold both the blade and tension spring 67 in spaced relation to the blade. Bracket 91 originally stamped out of sheet metal material, is bent into a U and has its bight section 92 firmly fastened to the side of the armature, remote from the relay core, in the vicinity of center leg 43 as by a number of spot welds. Each leg section of the bracket is stepped intermediate the bight and its ends to provide a shoulder 93 for receiving a part of blade regions 63a and 64a. The second generally U-shaped bracket 95 has the edges of its legs bent outwardly as seen in FIG. 5. These edges include tabs 96 which project through corresponding slots 97 located above shoulders 93 in bracket 91. In their assembled relation, best seen in FIG. 4, the bight sections of the respective brackets are disposed away from one another to create a large space for movement of the toggle meohansm. The two brackets are easily assembled together by first placing spring blade regions 63a, 64a on the shoulders of bracket 91, then compressing the edges of bracket 95' toward each other so that tabs 96 may be lined with slots 97 of bracket 91 over blade 61, and finally permitting the spring action of the bight section to force the legs apart so that the tabs enter the slots. The bias of bracket 95 will serve to hold the parts together, with blade 61 sandwiched between the brackets. By bending the edges and tabs slightly back toward the bight section of bracket 95, a tight pressure fit can be obtained between the parts. In this way, brackets 91 and 95 serve to space blade 61 a sufficient distance from armature 55 so that proper movement of tension spring 67 and arms 65, 66 is insured. If desired, blade regions 63a and 64a may include a lateral eat 98 which fits into a notch 99 furnished in the outer edge of bracket 91 for positioning brackets 91 and 95 at the correct location over spring 67.

Relay 40 also has a simple, yet highly effective impact element for mechanically assisting in the separation of contacts 55 and 56 from their engaged position. The element, which is denoted by numeral 101 in FIGS. 1, 3, 6, and 7, is of planar design, with a small stud 102, 103' projecting from each of its side faces. It is arranged between wall 73 and core leg 44, stud 102 being rock-ably seated in a complementary flanged hole 104 in the chamber Wall. Stud 103 rests against the side of core leg 44 near its free end. The free end 55b of armature 55, which swings toward and away from leg 44, is adapted to engage an extension 105 of the element at one side of the element fulcrum. A recess 107 out into the armature end allows element 101 to turn freely in its fulcrum. The other end of the element, beyond the pivot, has curved portion 108 adapted to engage blade 61.

Consequently, as best seen in FIG. 6 when relay coil 47 is energized and the armature is moved by magnetic attraction by the core to its operated or closed position (zero air gap), element extension 105 is engaged by the downward traveling armature, adjacent recess 107. This action causes element end 108 to swing into engagement with blade 61, adjacent contact 56, with a significant momentum. This in turn imparts a sudden motion to blade 61 as its spring 67 is moving over-center to complete the transfer of the switch contact 56 from its engaging to its non-engaging positions. If the contacts resist opening, as might occur in a welding condition, a high impact force can be developed by proper dimensioning of the element and correlating its motion with the over-center action of the movable contact system to insure an opening of the switch contacts. The element is reset by blade 61 as it moves contact 56 into the closed position due to its engagement with element end 108 which rocks the other elementupwardly toward the de-activated armature.

Further features and advantages of relay 40 will become more apparent from a description of the way in which the relay functions to control the start circuit. FIG. 7 schematically shows the switch relay operatively connected in a winding circuit to the single phase motor of the exemplification. Stationary contact 58 is in series with one side of the start winding which has its other side attached to terminal post 111, which is connected to one side of an alternating supply line 112. The stationary contact of the relay switch has its plate extension 62 attached to terminal post 113 which is connected to the other side of the power supply line 114 through a thermal protector device 115, a third terminal post 116 and a conventional manual single pole switch 117. The main winding is connected to power lines 112, 114 by having its terminations connected to terminal post 111, 113. Thus with the relay components and manual switch 117 disposed in the relative positions shown in FIG. 7, the two windings, are the start winding and the main winding, are energized in parallel across power lines 112, 114.

As the speed of the motor increases, the voltage induced in sensing coil 51 becomes greater and is applied to relay coil 47. This in turn causes an attraction on the magnetizable relay armature 55 proportional to the square of the applied voltage. Thus, when the magnetic force of attraction on the armature exceeds the bias of spring blade 61 which normally biases the armature toward the open position, and the net spring force on the armature, it is pulled down toward the core until over-center spring 67 and tension arms 65 and 66 cause switch contact 56 to be snapped away from the stationary contact.

Just prior to this snap action, the armature strikes impact element 101 and the element operates in the manner previously described. The point at which the contacts are opened by the armature is in effect a so-called cut out speed in the motor. If the motor stalls for any reason and the speed is reduced until the voltage induced in sensing coil 47 finally reaches a level sufliciently low such that the magnetic attraction on the armature is less than the net spring bias placed upon the armature, a cut back speed or condition is reached. At this time the bias of the spring 61 overcomes the magnetic attraction and returns the armature to its open position, thereby closing the contacts. The motor begins once again to develop starting torque to return the motor to running condition.

If desired, various calibrating means may be incorporated for controlling the operation of the relay. For instance, bracket 96 may include an integral spring arm 121 (FIG. 3) extending away from spring blade bend 61a. A rotatable screw 122, threadingly accommodated in support 78 above the free end of the arm, engages the arm. Rotation of the screw results in a linear change in its position relative to the arm and changes its net spring force which is in opposition to that of spring 61, defined between the brackets and support 62a, and therefore changes the net spring constant of spring blade 61. This is in effect a fine adjustment arrangement for blade 61, Screw 124 is provided in a similar fashion for engaging bracket to furnish control of the open-position of the armature 55. Rotation of screw 124 produces a linear change in its position relative to both the blade and the armature and adjusts the fully open position of the armature. The air gap dimension of the relay is thus regulated with a resulting control of the magnitude of the magnetic attraction across the air gap required to initiate downward motion of armature 55. Numeral 125 indicates a third screw, which is mounted directly over contact 56 and regulates the resetting force of the whole armature by controlling the open position of the movable contact.

In actual practice, relays constructed in accordance with the illustrated embodiment of FIGS. l-7, proved to be extremely rugged, performed quietly, had a long operative life and were modest in cost. When installed in a motor similar to that seen in FIG. 1 and described above of the resistance split, single phase type having four primary poles with a /3 horsepower rating, the relays operated trouble free for over 1,000,000 cycles and were capable of many more satisfactory cycles of operation when the tests were terminated.

FIGS. 8, 9, and 10 illustrate a second embodiment of the present invention in which identical parts to those shown in FIGS. 17 inclusive are identified by the same reference numbers. A comparison of the two switch relay embodiments shows that the switch relay of the second embodiment generally indicated by reference difierentiates principally from the first embodiment in the relay core and coil arrangement. More specifically, with reference to FIG. 10 the magnetizable core has four leg sections, 141, 142, 143, and 144, integrally united by yoke section 145. The free end 55b of armature 55 in this embodiment swings toward and away from outermost leg section 144. As in the first embodiment, the extreme outer edge of the leg upon which armature end 55a is seated has a rounded corner, indicated at numeral 146, so as not to interfere with the pivotal and sliding movement of armature 55 on leg 141 during operation.

The two inner legs 142 and 143, each accommodate similar coils 147 and 148 in spaced'relation to one another, each being wound of magnet wire and serially connected with the other as by a brazing or soldering operation. This connection is encompassed within insulating sleeve 149 which is in turn held in assembled relation between the coils by epoxy resin or the like. These coils, like coil 47 of the first embodiment, are suitably insulated from the core and other components. Fiber board insulators 152, 153, and 154, best seen in FIG. 10 may be used for this purpose. The upper or free ends of the inner two leg sections 142 and 143, remote from the yoke, are each provided withenlarged somewhat U-shaped notches 156 and 157 respectively. A rectangular bar 1580f copper or other suitable shadingcoil material is received in these notches and encircles the outermost ends 142a and 143a of legs 142 and 143. As a result, the core and armature have a pair of similar shaded paths in which one path passes through outermost leg 141 which supports armature end 55a. Since the flux density in this leg is slightly lower than inner legs 142 and 143, magnetic force permits axial slipping in reduced friction between the armature and leg 141 to provide good seating characteristics at this location. 7

In addition, by having armature 55 rest on either shaded leg end 142a or 143a as well as outermost leg 141 when the armature is in the closed or actuated position, that is, a zero air gap at these legs, the operation of the armature will be extremely. quiet, in spite of a possible 10 mil slippage relative to the relay core as the armature is moved toward and away from the core. Thus, the other legs should be lower than legs 141 and the other leg end on which the armature will rest in its closed position. In actual practice, a reduction of mils has been entirely satisfactory.

Another highly desirable feature of the relay of the second embodiment is the high reactance of resistance ratio; e.g., over unity, it is capable of producing for any given size relay. It can for instance provide a higher ratio than that of even the first embodiment. This means that more magnetic force on the armature can be obtained with the same or lower power or watts dissipation from the relay. This thermally attractive condition is particularly beneficial when the relay is utilized in a motor such as shown in FIGS. 1 and 2 where the overall operating temperature within shell 31'is a limiting factor on the kind of temperature sensitive components which may be used in the construction of the motor.

Since relay 140 operates essentially in the same manner as relay 40, which has already been set out in detail and has the same benefits and advantages, in addition to those specifically mentioned above, no further description will be included herein with regard to the second embodiment.

While in accordance with the patent statutes, I have described what at present is considered to be the preferred embodiments of my invention, it will be obvious to those skilled in the art that numerous changes and modifications may be made therein without departing from the invention and it is therefore aimed in the appended claims to cover all such equivalent variations as fall within the true spirit and scope of the invention.

formed of magnetizable material, an armature having a section generally disposed between said core and said cantilever blade, at least one electromagnetic coil accommodated by said core adapted to be energized during operation of the motor for actuating said armature,

means attaching said armature and spring blade in a fixed spaced relation to permit relative movement between said armature and over-center spring means as said spring means is operated by swinging movement of said armature, said cantilever spring blade and attaching means normally biasing the section of said armature away from said core, whereby the armature section swings toward said core and operates said over-center spring means in response to the actuation of said armature.

2. A switch relay for controlling the start winding of a single phase electric motor comprising first and second switch contacts, a cantilever spring blade carrying said first contact adjacent its free end for movement relative to said second contact, said blade having over-center spring means intermediate its end for producing snap action of said first contact into and out of engagement with said second contact, a core formed of magnetizable material, an armature having a section disposed between said core and said cantilever blade, at least one electromagnetic coil accommodated by said core adapted to be energized during operation of the motor for actuating said armature, means attaching said armature to the spring blade intermediate their respective ends in spaced relation to permit relative movement between said armature and over-center spring means as said spring means is operated by movement of said armature, said cantilever spring blade and attaching means normally biasing one end of said armature toward a seating engagement on the core and the armature. section normally away from the core toward an open position with said cantilever blade supporting said armature, whereby said armature section swings toward said core and operates said over-center spring means in response to the actuation of said armature.

3. A switch relay for controlling the start winding of a single phase electric motor comprising first and second switch contacts; cantilever spring blade supported at one end and carrying said first contact adjacent its free end for movement relative to said second contact; said blade having over-center spring means intermediate its ends for producing snap action of said first contact into and out of engagement with said second contact; a core formed of magnetizable material; an armature having a section generally disposed between said core and said cantilever blade; at least one electromagnetic coil accommodated by said core adapted to be energized during operation of the motor for actuating said armature; means attaching said armature and spring blade in a fixed spaced relation to permit relative movement between said armature and over-center spring means as said spring means is operated by swinging movement of said armature; said attaching means including a pair of generally U-shaped brackets having their bight sections disposed in opposed and spaced relation, with said blade being carried by said brackets intermediate said bight sections in spaced relation thereto; means securing said armature to the bight section of one of said brackets; said cantilever spring blade and attaching means normally biasing said section of the armature away from said core, whereby the armature section swings toward said core and operates said over-center spring means in response to the actuation of said armature.

4. The switch relay of claim 1 in which the spring blade has regions adjacent the over-center spring mean connected to the attaching means.

5. A switch relay for controlling the start winding of a single phase electric motor comprising first and second switch contacts; a cantilever spring blade supported at one end and carrying said first contact adjacent its free end for movement relative to said second contact; said blade having over-center spring means intermediate its ends for producing snap action of said first contact into and out of engagement with said second contact; a core formed of magnetizable material; an armature having a section generally disposed between said core and said cantilever blade; at least one electromagnetic coil accommodated by said core adapted to be energized during operation of the motor for actuating said armature; means attaching said armature and spring blade in a fixed spaced relation to permit relative movement between said armature and over-center spring means as said spring means is operated by swinging movement of said armature; said attaching means including a pair of generally U-shaped brackets having their bight sections disposed in opposed and spaced relation, with said blade,

being carried by said brackets intermediate said bight sections in spaced relation thereto; means securing said armature to the bight section of one of said brackets; the bracket disposed away from the armature having a spring arm extending away from the pivot of said armature; adjustable means engaging said arm for calibrating the net spring force on said armature; said cantilever spring blade and attaching means normally biasing the section of said armature away from said core, whereby the armature section swings toward said core and operates said over-center spring means in response to the actuation of said armature.

6. A switch relay for controlling the start winding of a single phase electric motor comprising first and second switch contacts; a cantilever spring blade supported at one end and carrying said first contact adjacent its free end for movement relative to said second contact; said blade being formed with an opening having a pair of opposed and spaced apart tension arms between the sides of the blade and a coil spring connected under tension to said tension arms to provide over-center spring means intermediate the ends of said blade for producing snap action of said first contact into and out of engagement with siad second contact; a core formed of ma netizable material; an armature having a section generally disposed between said core and said cantilever blade; at least one electromagnetic coil accommodated by said core adapted to be energized during operation of the motor for actuating said armature; means attaching said armature to said spring blade adjacent said tension arms in a fixed spaced relation to provide relative movement between said armature and said coil spring as said coil spring is operated by swinging movement of said armature, said cantilever spring blade and attaching means normally biasing the section of said armature away from said core, whereby said armature section swings toward said core and operates said coil spring in response to the actuation of said armature.

7. A switch relay for controlling the start winding of a single phase electric motor comprising first and second switch contacts; a cantilever spring blade carrying said first contact adjacent its free end for movement relative to said second contact; said blade having over-center spring means intermediate its ends for producing snap action of said first contact into and out of engagement with said second contact; a core formed of magnetizable material; an armature generally disposed between said core and said cantilever blade; at least one electromagnetic coil accommodated by said core adapted to be energized during operation of the motor for actuating said armature; means attaching said armature and cantilever spring blade intermediate their respective ends in spaced relation to permit relative movement between said armature and over-center spring means as said overcenter spring means is operated by movement of said armature; said cantilever spring blade and attaching means normally biasing the one end of said armature towards a seating engagement on the core and the other end normally away from the core toward an open position, whereby said other end swings toward said core and operates said over-center spring means in response to the actuation of said armature; and adjustable means engaging the free end of the blade at its open position to control the resetting force of the blade; said adjustable means controlling the open position of said armature for regulating the magnetic attraction required to overcome the bias of said blade.

8. In a switch relay for use in an electric motor, a core formed of magnetic material having four spaced apart upstanding leg sections joined together at one end by a yoke section, an armature havingone end pivoted adjacent one of the outermost leg sections for swinging the other end of the armature toward and away from the other leg sections, the free end of the two intermediate leg sections each including a notch intermediate.

the sides thereof, a shading coil disposed in said notches and surrounding the portion of said two intermediate leg sections facing one another with the remaining portions of said two intermediate legs sections being unshaded, a coil carried by each of said two intermediate leg sections arranged between said shading coil and said yoke section with said coils being connected in series relation and adapted to be energized for actuating said armature, said core producing a reactance to resistance ratio over unity when said coils are energized.

9. In-a switch relay for use in an electric motor, a core formed of magnetic material having at least four upstanding leg sections joined together at one end by a yoke section, an armature having one end maintained in seated relation on one of the outermost leg sections for swinging the free end of the armature toward and away from the other leg sections, the free end of at least one of the two intermediate leg sections accommodating a shading coil, the other of the outermost leg sections being unshaded, at leastone excitation coil carried by each of said two intermediate leg sections arranged between said shading coil and said yoke section adapted to be energized for actuating said armature, said one outermost leg section and said leg section accommodating said shading coil being raised above said other leg sections, said core producing quiet operation of said armature.

10. A switch relay for controlling the start winding of a single phase electric motor comprising first and second switch contacts, a cantilever spring blade carrying said first contact adjacent its free end for movement relative to said second contact, said blade having over-center spring means intermediate its ends for producing snap action of said first contact into and out of engagement with said second contact, a core formed of magnetic material having at least three spaced apart upstanding leg sections joined together at one end by a yoke section, an armature having one end pivoted adjacent one of the outermost leg sections for swinging the other end of the armature toward and away from the other leg sections, the free end of the other two adjacent leg sections each including a notch intermediate the sides thereof, a shading coil disposed in said notches and surrounding the portion of said two other leg sections facing one another, a coil carried by each of said two leg sections arranged between said shading coil and said yoke section with said coils being connected in series relation and adapted to be energized for actuating said armature, means attaching said armature and spring blade in a fixed spaced relation to permit relative movement between said armature and over-center spring means as said spring means is operated by movement of said armature, said cantilever spring blade and attaching means normally biasing one end of said armature away from said core whereby said free end swings toward said core and operates said over-center spring means in response to the actuation of said armature.

11. A switch relay for controlling the start winding of a single phase electric motor comprising first and second switch contacts; a cantilever spring blade supported at one end and carrying said first contact adjacent its free end for movement relative to said second contact; said blade having over-center spring means intermediate its ends for producing snap action of said first contact into and out of engagement with said second contact, a core formed of magnetizable material; an armature having a section generally disposed between said core and said cantilever blade; at least one electromagnetic coil accommodated by said core adapted to be energized during operation of the motor for actuating said armature; means attaching said armature and spring blade in a fixed spced relation to permit relative movement between said armature and over-center spring means as said spring means is operated by swinging movement of said armature; said cantilever spring blade and attaching means normally biasing said section of the armature away from said core, whereby said free end swings toward said core and operates said over-center spring means in response to the actuation of said armature; and impact means disposed adjacent said second contact including an angularly movable portion responsive to the movement of the armature section as the armature travels toward said core, said impact means augmenting the motion imparted to said cantilever blade away from said second contact by said over-center spring means.

12. A switch relay for controlling the start Winding of a single phase electric motor comprising first and second switch contacts; cantilever spring blade supported at one end and carrying said first contact adjacent its free end for movement relative to said second contact; said blade having over-center spring means intermediate its ends for producing snap action of said first contact into and out of engagement with said second contact, a core formed of magnetizable material; an armature having a section generally disposed between said core and said cantilever blade; at least one electromagnetic coil accommodated by said core adapted to be energized during operation of the motor for actuating said armature; means attaching said armature and spring blade in a fixed spaced relation to permit relative movement between said armature and over-center spring means as said spring means is operated by swinging movement of said armature; said cantilever spring blade and attaching means normally biasing said section of the armature away from said core, whereby the armature section swings towards said core and operates said over-center spring means in response to the actuation of said armature; and a rocker element mounted adjacent said second contact; said element having a pivot connection intermediate its ends, with one end being arranged in the path of movement of said armature adjacent said core, and with the other end being arranged to engage said cantilever spring blade, whereby said section of the armature engages said one element end as the armature section swings toward said core and pivots said other end i of the rocker element into sudden engagement with said cantilever blade to augment the motion of said first con- 12 tact imparted thereto by said over-center spring means as saidblade and first contact move away from second contact to the open position.

13. The switch relay of claim 2 in which the core is formed with first and second upstanding spaced apart outer leg sections and at least one intermediate leg section therebetween, with all of said leg sections being joined together at one end by a common longitudinal yoke section, said seating engagement of said one end of the armature being with the first outer leg section to provide relative longitudinal movement between the one armature end and thefirst outer leg section, and with a shading coil and an excitation coil being accommodated by at least some of the remaining upstanding leg sections, whereby said section of the armature is swung toward the second outer leg section of the core for operating said over-center spring means in rapid response to the actuation of said armature as said cantilever blade and attaching means swingably support said armature during the relative movev ment between said armature and said core.

14. In a switch relay having switch means for controlling the start winding of a single phase electric motor, a core formed of magnetic material having at least three spaced apart upstanding leg sections joined together at one end by a yoke section; an armature for operating the switch means having one end pivoted adjacent one of the outermost leg sections for swinging the other end of the armature toward and away from the other leg sections respectively between closed and open positions; said one outermost leg section being unshaded; the free end of two of the other adjacent leg sections each including a notch intermediate the sides thereof extending partially toward the yoke section; shading coil means disposed in said notches and surrounding the portion of said two other leg sections facing one another, with the remaining portions of said other two leg sections being entirely unshaded; at least one of the shaded core portions of said two other leg sections extending further away from the yoke section than the unshaded portions thereof for the armature to make engagement therewith when in the closed position; a coil carried by each of said two other leg sections arranged between said shading coil means and said yoke section, with said coils being connected in circuit and adapted to be energized for actuating said armature into the closed position, whereby the core is capable of producing a reactance to resistance ratio greater than unity to generate a high magnetic force on the armature for a given power input to the coils.

References Cited by the Examiner UNITED STATES PATENTS 1,837,928 12/ 1931 Trombetta 317l84 1,919,327 7/1933 Getchell.

2,540,022 1/1951 Rabenda 317-188 2,546,740 3/1951 Goldberg 317-184 2,749,485 6/ 1956 Oher et al 317184 2,883,488 4/1959 Curzon ZOO--84 3,016,435 1/ 1962 Schwartz 200-94 BERNARD A. GILHEANY, Primary Examiner.

'T. D. MACBLAIN, Assistant Examiner. 

1. A SWITCH RELAY FOR CONTROLLING THE START WINDING OF A SINGLE PHASE ELECTRIC MOTOR COMPRISING FIRST AND SECOND SWITCH CONTACTS, CANTILEVER SPRING BLADE SUPPORTED AT ONE END AND CARRYING SAID FIRST CONTACT ADJACENT ITS FREE END FOR MOVEMENT RELATIVE TO SAID SECOND CONTACT, SAID BLADE HAVING OVER-CENTER SPRING MEANS INTERMEDIATE ITS END FOR PRODUCING SNAP ACTION OF SAID FIRST CONTACT INTO AND OUT OF ENGAGEMENT WITH SAID SECOND CONTACT, A CORE FORMED OF MAGENTIZABLE MATERIAL, AN ARMATURE HAVING A SECTION GENERALLY DISPOSED BETWEEN SAID CORE AND SAID CANTILEVER BLADE, AT LEAST ONE ELECTROMAGNETIC COIL ACCOMMODATED BY SAID CORE ADAPTED TO BE ENERGIZED DURING OPERATION OF THE MOTOR FOR ACTUATING SAID ARMAUTE, MEANS ATTACHING SAID ARMATURE AND SPRING BLADE IN A FIXED 